Environmental groups, though, say the codes permit the use of chains dragged by bulldozers and blade ploughs that run counter to the recommendations in the Native Vegetation Regulation Review completed a year ago by agricultural consultant Joe Lane.

Self-assessable clearing should only include methods such as burning or clearing individual plants “with nil to minimal disturbance to soil and groundcover,” Mr Lane's review said.

The codes “will obviously lead to a lot more destructive land-clearing when we need to be protecting [native vegetation] as much as possible and moving to a more sustainable agriculture - not slash, burn and rip”, said Jeff Angel, director of the Total Environment Centre.

Pepe Clarke, chief executive officer of the Nature Conservation Council of NSW, said the prospect of large-scale clearing “creates a substantial environment risk” while placing landholders at risk of breaking laws if their self-assessment proves to be erroneous.

A spokesman for Ms Parker, though, said the draft invasive native species (INS) code only allows chaining and blade ploughing subject to conditions that protect soil, water and biodiversity. Such clearing methods cannot be used in threatened ecological communities or within certain distances of watercourses, and no clearing in areas of moderate to high land degradation risk for soil protection.

Ms Parker said the codes would be backed by “ongoing education” with Local Land Services providing advice.

Fiona Simson, president of the group, said the codes fall far short of what farmers had been expecting and still require two weeks’ notification for ‘‘routine land management’’.

Cameron Rowntree, a native vegetation spokesman for NSW Farmers, said farmers should be allowed to thin native vegetation and remove invasive species without a code.

“Farmers are being treated like mugs,” he said. “Our productivity is being absolutely crushed as a result of these impractical rules.”

Mr Angel of the Total Environment Centre said proposed spot audits would do little to protect sensitive habitat, such as paddock trees that are home to endangered animals and birds: “How would you know what was there before it was cleared?”

Mr Clarke said the new codes open the way for hundreds of thousands of trees to be felled, breaking wildlife corridors and degrading the beauty of the landscape.

The government said the codes, on exhibition for comment until May 26, aim to create a “mosaic” of native vegetation while removing or thinning native plants that have spread beyond their original range.

Paddock trees that are felled must be balanced by “setting aside” existing areas of native bush or allowing natural regeneration to occur, the government said.

The spokesman for Ms Parker said that only paddock trees in cultivated areas can be cleared. "This is an area that is cropped, ploughed or fallow or covered in perennial or annual exotic pasture," he said. All big paddock trees, with a diameter of 80 centimetres or more, remain protected.